# Full text of "Handbook Of Chemical Engineering - I"

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```HANDBOOK
OF
CHEMICAL ENGINEERING
SECTION I
POWER GENERATION AND TRANSMISSION
BY W. D.
Definitions. — The foot-pound is the unit of work. One foot-pound is the work done in raising a 1-lb. weight a distance of 1 ft. vertically against gravity. The heat unit (British thermal unit, B.t.u.) is also a unit of work. It is Hso of that amount of heat necessary to raise the temperature of 1 Ib. of water from the freezing point to the boiling point. One large calorie = 2.2046 X % = 3.968 B.t.u. One British thermal unit = 778 ft.-lb. The horsepower is the unit rate of doing work. One horsepower = 33,000 ft.-lb. per minute = 550 ft.-lb. per second = 2,545 B.t.u. per hour = 42.42 B.t.u. per minute. The horsepower-hour is a measure of work done. One horsepower-hour = 60 X 33,000 = 1,980,000 'ft.-lb. or 2,545 B.t.u. Concurrent units are the kilowatt and kilowatt-hour. One kilowatt = 1.34 hp. One kilowatt-hour = 2,650,000 ft.-lb. = 3,410 B.t.u. Registering instruments measure kw.-hr. If the work done in 5 hr. is 50,000 kw.-hr., the average load during that period was 10,000 kw. or 13,400 hp.
Load may be expressed in horsepower or kilowatts; or, for boilers and process work, in pounds of steam per hour; or as measured by consumption (pounds of coal per hour). The load curve is a graph of load against time. Figure 1 gives load at 2-hr. intervals for 1 day. Each ordinate is the quotient of kilowatt-hours registered in 2-hr, by 2. An indicating instrument would show fluctuations above and below the line. The base may be successive days in a month or year.